Mankind has used oars in simple pivoting oarlocks to propel his boats for over 3,000 years but such an arrangement has two distinct disadvantages. If no separate tiller is employed on the boat, the rower must steer his own course by judicious use of the oars. However, due to the normal rowing arrangement the rower must sit backwards to the course of the boat so that he can use his powerful leg and back muscles most effectively. Therefore he cannot see where he is going but only where he has been. This means that in any hands other than those of an expert, rowboats do not follow the desired straight line path when being rowed since it is normal for the rower to be stronger and therefore accidentally apply more force on one side than the other. This tends to gradually turn the boat into his weak side. Once the turn gets large enough to notice, it must be corrected by an extra stroke to the weak side or by a stronger stroke on the weak side.
The second disadvantage of the well known means to row a boat is that there is a substantial sideways component to the force applied by an oar both at the start and at the end of a stroke which does nothing to propel the boat but expends a considerable amount of energy from the rower. It has therefore been desired to develop an oar lock system which allows the oarsman to face forward and which enables him to apply a larger percentage of his total energy to propelling the boat forwardly.